2012 Marked by Infectious Diseases

According to Reuters.com, weather conditions contributed to the worst outbreak of West Nile virus since 2003 and an unusual outbreak of Hantavirus in Yosemite National Park killed three of the infected 10 visitors.

CDC and state officials have said that rainfall in the spring and extreme summer heat contributed to the severity of the West Nile virus outbreak by affecting mosquito populations. As of December 11, 5,387 cases of West Nile virus had been reported in 48 states, resulting in 243 deaths, the CDC said in its final 2012 update on the outbreak.

Invasive Species News Video

Many invasive species, or pests of foreign origin, have become established in the United States. Watch this video to learn more about brown marmorated stink bugs, spotted lanternflies, Asian longhorned ticks and more.